Process for applying lubricant coatings



July 5, 1966 w. J. PHYsloc m PRocEss Fon APPLYING LUBRVICANT coATINGs 2 Sheets-Sheet 1 Filed June 28. 1962 III,

July 5, 1966 w. J. PHYsloc nl 3,259,519

Y PROCESS FOR APPLYING LUBRICANT COATINGS Filed June 28. 1962 2 Sheets-Sheet 2 INVENTOR W/Zlz's Physica? www? United States Patent O 3,259,519 PROCESS FOR APPLYING LUBRICANT COATINGS Willis J. Physioc III, Boonsboro, Md., assignor, by mesne assignments, to The Pangbom Corporation, Hagerstown, Md., a corporation of Delaware Filed June 28, 1962, Ser. No. 205,967 2 Claims. (Cl. 117-100) The present invention relates to coating metal or molded plastic parts, metal powders, plastic material powders to be used for forming molded plastics, etc., with a dry lubricant, such as molybdenum disulfide.

It has been found advantageous, for instance, to pre-lubricate metal pieces which are to be used in apparatus at areas not accessible for ordinary liquid lubrication to render them rust and corrosion proof. Some examples are pieces to be subsequently mated, buried mechanisms in business machines, hinges and pivots in aerodynamic linkages, and home and oce equipment, such as kitchen mixers, micrograph machines as well as fishing reels.

It is also known that metal bars can be better drawn or forged if they are first cleaned and dry lubricated.

Molybdenum disulfide (molybdenite) has been widely used as a dry lubricant for metal parts. In this cornpound, the sulfur-molybdenum-sulfur layers slide easily on one another. Within the individual layers, however, the cohesive forces between Mo and S atoms are very storng and thus resist penetration by surface asperities of the metal being lubricated. MOS?l adheres well to metal surfaces because the exposed sulfur atoms have a strong affinity for metals.

When applying the molybdenum disulfide lubricant coatings in the past, it was found that resin binder carriers or chemical conversion carriers were preferred to provide better adherence of the lubricant to the metal surfaces. For instance, thermosetting or thermoplastic resin carriers, such as alkyls, vinyls, epoxides, phenolics, melamines, as well as inorganic binders of sodium silicate, phosphates, borates, fluoride-phosphates and sodium hydroxide have been used.

With regard to the above, thermoplastic binders are aircured and have a shorter wear life than the thermosetbased oven-cured types. The thermoplast air-cured processing is generally used for parts already installed in a machine, for materials that will not taken an oven-cure, and Y for parts too big for processing in an oven.

The oven-cured thermosetting resins have better corrosion resistance as well as better wear life. Switching from an air to an oven-cured coating can increase wear life as much as 300%.

The inorganic bonded coatings show promise, once the problems of water solubility, application methods and coat can be surmounted.

It has been found that if the metal parts are first pretreated to descale, mechanically roughen the surface to form potential lubricant storing pockets, and otherwise clean the metal parts, the lubricant subsequently applied in a second step by tumbling, spraying, brushing, etc. will adhere much better and longer to the metal surfaces since the bond between the metal piece and lubricant is improved.

It is, therefore, an object of the present invention to provide a new and novel proces for lubricating metal parts, metal powders, a plastic material powder to be used for forming molded plastics, etc.

A further object of the invention is to provide a new ice and novel process for lubricating metal parts without the necessity of using binders or conversion coatings for the lubricant.

Another object is to provide a new and novel process for simultaneously lcleaning and dry lubricating metal parts.

Another object of the invention is to provide a new and novel process for lubricating metal parts by transferring dry lubricant from lubricant carrying metal work elements to the metal parts to be coated.

Still another object is to provide a new and novel process for simultaneously cleaning and lubricating metal parts through vibratory contact with metal cleaning abrasive elements carrying the dry lubricants.

A further object of the invention is to provide a new and novel process for simultaneously cleaning and lubricating met-al parts, which may be tumbled, by a blast contact with metal cleaning abrasive elements carrying the dry lubricants.

Still a further object of the invention is to provide a methodfor providing the metal work or abrasive elements of the above objects wtih a dry lubricant coating.

Further objects and advantages will become apparent from a study of the following description and drawing wherein: Y

FIGURE l is a section showing the manner in which the metal cleaning work or 'abrasive elements are coated with a dry lubricant;

FIGURE 2 is a section showing how the dry lubricant carrying metal cleaning work or abrasive elements simultaneously clean and lubricant metal parts through vibratory action;

FIGURE 3 is a View showing how the dry lubricant carrying metal cleaning work or abrasive elements simultaneously clean and lubricate metal parts by a blast contact therewith; and

FIGURE 4 shows a continuous process vibrating machine which can be used with the process of the present invention.

In the drawing, the lubricant particles and the abrasive shot are slightly exaggerated in size to better show the invention.

Referring now to FIGURE 1 of the drawing, there is shown a vibratory tube 1 in which are placed the metal cleaning work or abrasive elements 3 and a dry lubricant material 5 in powder form for metal pieces. The metal cleaning work pieces 3 are preferably small, steel, shot pieces of varying shape including sharp-edged shape. The dry lubricant is in the form of a powder and may be any of the well known dry lubricants for metal. Molybdenum disulfide is a preferred lubricant for the reasons given in the introductory portion of the specification.

As seen in FIGURE l, vibratory means 7 for the tub is shown. Although any suitable vibratory assembly may be used, the specific embodiment of the vibratory assembly shown in FIGURE l is disclosed, other than the specific design of the air cushion supports 10 yand 10a, in the patent applica-tion of Ralph W. Moore, Serial No. 4,908, led January 27, 1960, entitled Vibratory Finishing now Patent No. 3,063,207. Further description of the vibratory means will, therefore, not be given here.

In view of the metal attractive forces within the molyb- .denite, the constant vibration of the tub 1 and the resultant impingement -action between the lubricant and the abrasive, the lubricant is gradually transferred to the abrasive surfaces until the abrasive is completely covered, coated or saturated. Abrasive metal cleaning elements or shot containing on ytheir surface a transferable coating of solid lubricant material are thereby provided.

A suitable surface condition such as obtained with shot blasting, acid or alkaline etching, heat or other means well known to the trade, like phosphating, may be incorporated in the tub along with the lubricant.

In FIGURE 2, there is shown the vibratory tub 1 disclosed in the same Moore application as for FIGURE l) used for simultaneously descaling, cleaning and for applying a lubricant to metal pieces 9. Some examples of these pieces 9 may be hidden elements which are to be used in business machines, hinges and pivots to be used in aerodynamic linkages, homes and office equipment, such as mixers, micrograph machines and fishing reels. However, any metal parts can be so treated if they are of a suitable size and weight to be satisfactorily vibrated in the tub 1, the size of which may also be varied.

With the metal piecesl 9, there are also placed in the tub the lubricant coated shot or abrasive work pieces 11 found in FIGURE 1 of the drawing. Through constant movement, including rotation and/ or tumbling of the work pieces 9, the impingement between the coated shot 11 and the pieces 9 as well as the attractive force mentioned above, the pieces 9 are simultaneously descaled, cleaned and coated with the dry lubricant which is transferred from the shot surfaces 11 during the vibratory action period.

If the shot 11 should contain a binder or chemical conversion coating of dry lubricant, such as discussed above which is applied as in FIGURE 1, the tube of FIGURE 2 is'subsequently heated while still vibrating by a suitable heating unit affixed to the tub (not shown) after a certain time period of vibratory action has expired in which the lubricant has been transferred from the shot 11 to the work pieces 9. On the other hand, the tub can be heated at low temperature initially and the temperature can gradually be increased during the vibration period. The above two approaches might prevent the binder from setting up on the abrasive shot pieces before being transferred.

FIGURE 3 shows a roto blast machine 15 whereby the lubricant coated abrasive shot 11 is thrown with great force by a rotary wheel 17 against metal pieces 19 which may be metal bars, cylinders, etc., simultaneously descaled, cleaned and lubricated. The constant impingement of the shot against the surfaces of the metal pieces gradually cleans the surface and brings about the transfer of the lubricant from the abrasive to the metal parts. Any suitable blast machine can be used for the present method. The embodiment shown in FIGURE 3 is disclosed in Patent No. 2,604,734. Other specific examples of blast machines are disclosed in the following patents and patent applications: 2,869,289; 2,816,466; 2,771,189; 2,753,644; 2,732,666; 2,742,929; 2,719,387; 2,716,310; Serial No. 829,078, filed July 23, 1959, now Patent No. 3,048,947, and Serial No. 80,587, filed January 4, 1961, now Patent No. 3,081,580, both entitled Abrasive Blasting Apparatus and both in the names of George W. Powell and Maxwell E. Fahrney disclose tumbling assemblies in combination with the blast apparatus.

As opposed to the batch-type vibrating machine in FIGURES 1 and 2, a continuous vibrating machine may also be used as shown in FIGURE 4 of the drawing. Here, the parts to be lubricated are supplied to an endless conveyor belt 20 from a metering bin 22 positioned thereabove at the feed end of the belt. The parts to be lubricated are deposited in the vibratory tub 24 along with steel, shot or abrasive carrying the lubricant and fed to the tub 24 through feed spout 26. The vibratory or `gyratory motion of the tub 24 produced by the mechanism shown in FIGURE 1 of the drawing advances the parts as well as the lubricant carrying shot to the opposite end of the tub 24 at which point it is advanced over the end of the tub 24 to fall into a screen-type separator and conveyor 28 wherein the now lubricated parts 30 are retained on the vibratory screen 28 while the shot and the other abrasive pass through the screen to be connected in connectoi 32 from which point it is carried to a suitable washer unit 34 and into an elevator unit 36 to be again introduced into feed spout 26 for the tub 24.

It should also be pointed out that different type cushion supports may be used for the vibratory tubs shown in FIGURES 1 and 4. Other suspension means which may be used for the vibratory tub are shown in the following patent applications: Serial No. 168,146, filed January 23, 1962, now Patent No. 3,163,966; Serial No. 188,659, filed April 19, 1962, now Patent No. 3,165,389; and Serial No. 4,908, filed January 27, 1960, now Patent No. 3,063,207. All of these embodiments as described in the application aid in providing vibratory as well as gyratory motion for the tub and its contents.

If molded plastics, such as melamineand urea formaldehydes, phenalics, silicones, dialkyl phthalate, etc. are to be lubricated, the present invention provides a method whereby the plastic material in powder or particle form before molding can be vibrated in a tub with the lubricant coated shot or the lubricant by itself to incorporate the lubricant directly into the plastic material to be subsequently molded. However, the molded parts may also be finished and coated in accordance with the above-described process. If the metal parts to be lubricated are already cleaned then the parts can be placed with the lubricant powder or particles directly into the tub to be vibrated together whereby the parts are directly lubricated by the powder. If the coating is a heat-setting binder lubricant coating, the tub is heated as mentioned above.

It is also possible to use a wet lubricant instead of the dry molybdenite in the vibratory or blast process described above. The usual lubricating oils can be satisfactorily used.

Another feature here is that those internal portions of the roto blast machine itself which come in contact with the blast shot also receive a lubricant coating. These parts of the machine include the rotary wheel itself, the impeller for feeding the shot to the wheel, the assembly for holding or supporting the pieces to be treated, bearings, etc. Such part lubrication increases the wear life of the machine itself.

The methods described above may also be used in applying lubricants, wet or dry, to elastomers, such as natural or synthetic rubbers.

The advantages of the present invention are many. Among the advantages: the two separate operations heretofore required of first cleaning and descaling the metal pieces and then subsequently applying a lubricant can now be accomplished simultaneously in one step.

Actually, it is not necessary now to use the chemical conversion coatings, plastic binders, etc. as mentioned above to apply a lubricant to the metal parts since the lubricant coatings are firmly plated onto the metal parts by the impingement action of the process of the present invention.

Metal bars which can be treated in the one step operation according to the invention can be immediately drawn or forged.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that, within the scope of the appended claims, the invention may he practiced otherwise than as specifically described.

What is claimed is:

1. A process for simultaneously cleaning and applying lubricant coating to articles which comprises loading abrasive shot into a vibratory container, loading solid lubricant in particulate form into said vibratory container, vibrating said container until the lubricant coats the abrasive shot, inserting the articles into an abrasive blasting machine, and blasting the lubricant coated abrasive shot against the articles in the blasting machine to transfer the lubricant coating to the articles while the articles are simultaneously being cleaned.

2. The process of claim 1 wherein the abrasive shot is metal, and the lubricant is molybdenum disulfide.

References Cited bythe Examiner UNITED STATES PATENTS Brace 117-109 Kalischer 117-127 X Louis 117-211 Louis 117-109 5 WILLIAM D. MARTIN, Primary Examiner.

RICHARD D. NEVIUS, Examiner.

R. E. ZIMMERMAN, S. W. ROTHSTEIN,

Assistant Examiners. 

1. A PROCESS FOR SIMULTANEOUSLY CLEANING AND APPLYING LUBRICANT COATING TO ARTICLES WHICH COMPRISES LOADING ABRASIVE SHOT INTO A VIBRATORY CONTAINER, LOADING SOLID LUBRICANT IN PARTICULATE FORM INTO SAID VIBRATORY CONTAINER, VIBRATING SAID CONTAINER UNTIL THE LUBRICANT COATS THE ABRASIVE SHOT, INSERTING THE ARTICLES INTO AN ABRASIVE BLASTING MACHINE, AND BLASTING THE LUBRICANT COATED ABRASIVE 